Jon Major

Science and Products

• Science
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  October 25, 2013

  Dam removal: synthesis of ecological and physical responses

  Dam decommissioning is rapidly emerging as an important river restoration strategy in the U.S., with several major removals recently completed or in progress. But few studies have evaluated the far-reaching consequences of these significant environmental perturbations, especially those resulting from removals of large (>10-15 m tall) structures during the last decade. In particular, interactions b

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  John Wesley Powell Center for Analysis and Synthesis

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  October 25, 2013

  Dam removal: synthesis of ecological and physical responses

  Dam decommissioning is rapidly emerging as an important river restoration strategy in the U.S., with several major removals recently completed or in progress. But few studies have evaluated the far-reaching consequences of these significant environmental perturbations, especially those resulting from removals of large (>10-15 m tall) structures during the last decade. In particular, interactions b

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• Data
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  November 16, 2022

  Digital elevation model of South Fork Toutle River, Mount St. Helens, based on June–July 1980 airborne photogrammetry

  The lateral blast, debris avalanche, and lahars of the May 18th, 1980, eruption of Mount St. Helens, Washington, dramatically altered the surrounding landscape. The eruption produced mudflows in the South Fork Toutle River basin, which drains the western slopes of the volcano. Orthophotography was acquired shortly after the eruption (June 19 and July 1). Survey extent includes South Fork Toutle Ri

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  Volcano Science Center
• Publications

  My research publications can be parsed among various disciplinary studies. A full listing can be found on my Google Scholar profile (search for this via your web browser) and under the publications tab listing below. Publication topics include:

  - Landslides, debris flows, and slurry rheology

  - Volcanic eruptions and volcaniclastic processes (lahars, pyroclastic flows)

  - Hydrogeomorphic responses to eruptions

  - Geomorphic and ecologic responses to dam removals

  - Photogrammetric analyses of eruptive processes

   

  Filter Total Items: 99

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  August 25, 2022

  Can lava flow like water? Assessing applications of critical flow theory to channelized basaltic lava flows

  Flowing lava and water have dramatically different physical properties but can form similar hydraulic structures, including undular hydraulic jumps, or standing wave trains. In water flows, undular hydraulic jumps are evidence of critical flow (Froude number ∼1) and open-channel hydraulic theory provides a powerful tool for estimating flow depth and velocity. Monitoring these parameters in an acti

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  Volcano Hazards, Volcano Science Center

  July 14, 2022

  Subaerial volcaniclastic deposits — Influences of initiation mechanisms and transport behaviour on characteristics and distributions

  Subaerial volcaniclastic deposits are produced principally by volcanic debris avalanches, pyroclastic density currents, lahars, and tephra falls. Those deposits have widely ranging geomorphic and sedimentologic characteristics; they can mantle, modify, or create new topography, and their emplacement and subsequent reworking can have an outsized impact on the geomorphic and sedimentologic responses

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  Volcano Hazards, Volcano Science Center

  March 18, 2021

  Lava effusion rate evolution and erupted volume during the 2018 Kīlauea lower East Rift Zone eruption

  The 2018 eruption on the lower East Rift Zone of Kīlauea Volcano produced one of the largest and most destructive lava flows in Hawai’i during the past 200 years. Over the course of more than 3 months, twenty-four fissures erupted, and the rate of lava effusion varied by two orders of magnitude, with significant implications for evolving flow behavior and hazards. Syn-eruptive data were collected

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  Volcano Hazards, Volcano Science Center

  January 22, 2021

  Experimental studies of deposition by debris flows: Process, characteristics of deposits, and effects of pore-fluid pressure

  No abstract available. 

  December 9, 2020

  Effective hydrological events in an evolving mid‐latitude mountain river system following cataclysmic disturbance—A saga of multiple influences

  Cataclysmic eruption of Mount St. Helens (USA) in 1980 reset 30 km of upper North Fork Toutle River (NFTR) valley to a zero‐state fluvial condition. Consequently, a new channel system evolved. Initially, a range of streamflows eroded channels (tens of meters incision, hundreds of meters widening) and transported immense sediment loads. Now, single, large‐magnitude or multiple moderate‐magnitude ev

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  Volcano Hazards, Volcano Science Center

  May 18, 2020

  Ten ways Mount St. Helens changed our world—The enduring legacy of the 1980 eruption

  Mount St. Helens was once enjoyed for its serene beauty and was considered one of America’s most majestic volcanoes because of its perfect cone shape, similar to Japan’s beloved Mount Fuji. Nearby residents assumed that the mountain was solid and enduring. That perception changed during the early spring of 1980. Then, on May 18, 1980, following 2 months of earthquakes and small explosions, the vol

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  Natural Hazards, Volcano Hazards, Volcano Science Center

  May 15, 2020

  Mount St. Helens at 40

  No abstract available. 

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  Volcano Hazards, Volcano Science Center

  April 24, 2020

  Lessons from a post-eruption landscape

  From March to May 1980, magma rose high into Mount St. Helens (MSH), swelling and—as it turned out—destabilizing its north flank. Scientists knew the volcano had been highly active at times over the past 40,000 years, but the mountain, located amid the Cascade Range in southwestern Washington, had been mostly quiet since the mid-19th century. The collapse of the north flank on 18 May shattered tha

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  Volcano Hazards, Volcano Science Center

  April 10, 2020

  A multidecade analysis of fluvial geomorphic evolution of the Spirit Lake blockage, Mount St. Helens, Washington

  Volcanic eruptions can affect landscapes in many ways and consequently alter erosion and the fluxes of water and sediment. Hydrologic and geomorphic responses to volcanic disturbances are varied in both space and time, and, in some instances, can persist for decades to centuries. Understanding the broad context of how landscapes respond to eruptions can help inform how they may evolve, and therefo

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  Volcano Hazards, Volcano Science Center

  November 18, 2019

  Field trip guide to Mount St. Helens, Washington—Recent and ancient volcaniclastic processes and deposits

  This field guide explores volcanic effusions, sediments, and landforms at Mount St. Helens in Washington. A detailed synopsis outlines the eruptive history of Mount St. Helens from about 300,000 years ago through 1980 and beyond.The five days in the field include about 28 stops and 12 potential stops. Exposures in valleys surrounding Mount St. Helens reveal records of diverse Pleistocene and Holoc

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  Volcano Hazards, Volcano Science Center

  July 1, 2019

  Toutle River debris flows initiated by atmospheric rivers: November 2006

  In early November, 2006, an atmospheric river brought heavy rainfall and high freezing levels to the Pacific Northwest. Without snowpack to buffer the hydrologic response, the storm caused widespread landslides and debris flows in drainages sourced from every central Cascades volcano. At Mount St. Helens, in southwestern Washington State, intense rainfall in the crater of the volcano caused at lea

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  Volcano Hazards, Volcano Science Center

  April 8, 2019

  Multidecadal geomorphic evolution of a profoundly disturbed gravel-bed river system—a complex, nonlinear response and its impact on sediment delivery

  A 2.5-km3 debris avalanche during the 1980 eruption of Mount St. Helens reset the fluvial landscape of upper North Fork Toutle River valley. Since then, a new drainage network has formed and evolved. Cross-section surveys repeated over nearly 40 years at 16 locations along a 20-km reach of river valley document channel evolution, geomorphic processes, and their impacts on sediment delivery. We ana

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  Volcano Hazards, Volcano Science Center
• News
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  January 17, 2021

  January 17, 2021 Mount Hood Earthquake Swarm

  An earthquake swarm at Mount Hood is ongoing. The earthquakes are associated with regional faulting and are not a sign of changes in volcanic activity...

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  September 28, 2017

  Volcano Watch — Legacy of the Mount St. Helens 1980 eruption still defies perfect solution

  Thirty-seven years after the May 18, 1980, eruption of Mount St. Helens, Washington, scientists, engineers, land managers, and Federal, State, and...

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